Want to shed some pounds? You're more likely to be successful if you stand to gain --or lose -- some money.

In the short term, financial rewards can provide strong incentive to ditch bad habits, says one of the researchers.

In a new study, overweight or obese dieters who were trying to shed weight lost 13 to 14 pounds in four months if they stood to win or lose a bit of money. The dieters who had no motivation -- other than to look better and feel healthier -- lost only about 4 pounds.

However, the results were less dramatic after seven months. The cash-incentive group regained weight, for a total 6- to 9-pound weight loss, compared to 4.4 pounds in those who did not have money at stake, according to the study published Tuesday in the Journal of the American Medical Association.

Kevin Volpp, M.D., Ph.D., one of the study's authors and the director of the Center for Health Incentives at the Leonard Davis Institute for Health Economics, in Philadelphia, Pennsylvania, says providing a small financial incentive helped people forget what they were giving up -- fatty fare like burgers and fries, rich desserts, or alcohol.

This mix of frequent rewards, both large and small, helped dieters to stay on track -- and on the scale. "It was a tangible reminder for why they are changing their behavior," Dr. Volpp says.

The study included 57 people ages 30 to 70 -- almost all men -- who were overweight or obese. One group contributed between $0.01 and $3.00 to a fund each day, which was matched by researchers. If they met their weight-loss goal, the money was refunded at the end of the month. A second group had no financial incentive, and a third group qualified for daily $3 prizes, plus less frequent $10 to $100 prizes, if they lost weight.

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"First off, this certainly doesn't address having people lose weight in a healthy manner," says Samantha Heller, RD, the host of Doctor Radio and a contributor to Health magazine. "You can lose weight eating only hot dogs, but that's not healthy."

Also, what happens when the reward system is removed? If individuals don't have the right education in place, Heller says, they're apt to fall back on their bad ways.

Heller also says the results may not apply to all dieters, citing the small study group and the fact that about 95 percent of the participants were male.

Dr. Volpp says he has no reason to believe that women would have a tougher time with a rewards-based program than men. However, the researchers did find that black dieters (with an average weight loss of 4.2 pounds) seemed to have a harder time losing weight than white dieters (with an average of 14.7 pounds).

At least in the short term, financial rewards can provide strong incentive to ditch bad habits, says Dr. Volpp. And weight-loss programs don't have to be expensive, even if they're offering financial rewards.

In the study, participants had a one-on-one session, in which they discussed diet and exercise strategies, with a dietitian, and then were on their own. They didn't have a strict meal plan or detailed exercise routine, and devised their own slim-down plan. Text messages were used to clue in participants regarding their progress.

If they didn't shed weight, they got a second chance. Lagging participants were given a fresh start each month, plus a chance to win their money back if they did better. Those who exceeded their goals could lose weight at a slower rate.

The second chance for lagging dieters seemed to be a good motivator. Participants were sent a text-message reminder of what they would have won had they shed the weight, which did spur some to take their diet up a notch.

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Obesity is expensive: An April 2008 report from the Conference Board found that obese employees cost businesses an estimated $45 billion a year for medical expenditures and work loss. If all overweight employees had financial incentives to shed weight, businesses might find both their workers and their bank accounts healthier.

With the economy sinking and waistlines swelling, some experts argue that an incentive-based approach to health care could help businesses with their budget while simultaneously putting a little cash back into employees' pockets. Health.com: How to save money on organic foods

"It's very easy to keep procrastinating when it comes to behavior changes," says Dr. Volpp. "But this gives you a tangible reason not to procrastinate any longer."